MOSQUITOES IN GENERAL 25 



cases need an individnal or a community be deterred 

 even for a moment from attempting- remedial work 

 against mosquitoes by the idea that the mosquito supply 

 is likely frequently to be renewed by flights from long 

 distances or even from distances of much more than a 

 single mile. A far more serious source of re-establish- 

 ment of the mosquito sui)ply will be considered in the 

 following section. 



Carriage of Mosquitoes by Railway Trains and other 

 Conveyances. 



That mosquitoes are carried by railway trains must be 

 a matter of common observation to everyone who travels. 

 That this method of distribution is and has been a very 

 important one, has, however, been rather g-enerally over- 

 looked. It is said that mosquitoes were unknown in 

 Hawaii until brought over in sailing vessels from the 

 United States. On these sailing vessels they had proba- 

 bl}'^ bred more or less continuously in the water-barrels, 

 and when once introduced into the islands they bred Avith 

 g-reat facility in the swamps and freshwater ponds, and 

 to-day these insects are said to be very abundant there. 



Beyond the statement which occurs in Nuttall's mono- 

 graph (1890), where the probable influence of Avinds, rail- 

 ways, and ships in the dissemination of mosquitoes is 

 briefly mentioned, the subject had received practically no 

 consideration until it was brought out in the liulletin en- 

 titled, " Notes on Mosquitoes," prejiared by the author 

 and published by the United States Department of Agri- 



